Understanding optical reflectance contrast for real‐time characterization of epithelial precursor lesions

Abstract

Detecting early‐stage epithelial cancers and their precursor lesions are challenging as lesions could be subtle and focally or heterogeneously distributed over large mucosal areas. Optical coherence tomography (OCT) that enables wide‐field imaging of subsurface microstructures in vivo is a promising screening tool for epithelial diseases. However, its diagnostic capability has not been fully appreciated since the optical reflectance contrast is poorly understood. We investigated the back‐scattered intensities from clustered or packed nanometer scale intracellular scatterers using finite‐difference time‐domain method and 1‐μm resolution form of OCT, and uncovered that there existed correlations between the reflectance contrasts and the ultrastructural clustering or packing states of these scatterers, which allows us to interpret the physiological state of the cells. Specifically, both polarized goblet cells and foveolar cells exhibited asymmetric reflectance contrast, but they could be differentiated by the optical intensity of the mucin cup due to the different ultrastructural make‐ups of the mucin granules; keratinocytes could demonstrate varied cytoplasmic intensity and their cytoplasmic contrast was closely correlated with the packing state of keratin filaments. Further preliminary study demonstrated that these new understandings of OCT image contrast enables the characterization of precancerous lesions, which could complement the current morphology‐based criteria in realizing “virtual histology” and would have a profound impact for the screening and surveillance of epithelial cancers.

The establishment of COPD organoids to study host-pathogen interaction reveals enhanced viral fitness of SARS-CoV-2 in bronchi

“…The µOCT technology has been described previously 113 – 116 . In brief, the µOCT system included a Spectral-domain OCT (SD-OCT) imaging console and a benchtop probe.…”

Three‐dimensional morphological revealing of human placental villi with common obstetric complications via optical coherence tomography

“…Here the pixel‐resolution rescale operations were performed on the 3D image volumes, and a specific index mentioned in Section 2.3 was chosen to numerically rescale the axial pixel resolution to achieve that the acquired 3D image volumes have the same pixel resolution along different axis directions, so it can be more convenient to observe and measure the 3D morphology of human placental villi. Meanwhile, here we assumed the refractive index of the sample over a wide range of wavelengths as ~1.38, following the References 30 , 31 to estimate the OCT axial optical resolution in the sample, which was ~1.7 μm.…”

Real-time delineation of basement membrane in human oral and esophageal mucosa with micro-optical coherence tomography

“…μOCT, a cellular-resolution OCT system, provides the real-time cross-sectional images of tissues with a spatial resolution of 1-2 μm which is around one order of magnitude higher than the standard OCT technology. Previous studies have demonstrated its capability to recognize subcellular structures underneath the surface in tissues like atherosclerotic coronary artery wall [7], oral mucosa and esophageal mucosa [19]. To uncover the scattering characteristics of basement membrane underlying the epithelium, in this study we simulated the scattering feature of basement membrane numerically and validated the simulation results in human oral and esophageal mucosa experimentally using μOCT.…”

“…A previously developed µOCT system was used in this study [19,20]. Briefly, the light went to reference arm and sample arm respectively after being divided by a beam splitter (PAFA-X-4-B, Thorlabs, New York).…”